Device for transporting toners to/from a toner deposition unit in an electrophotographic printing or copying device

ABSTRACT

In a device for transporting toner in an electrophotographic printing or copying device, a rotatable cylinder has a cylinder sheath. The cylinder such includes a metallic layer having a surface with a roughness search that at least one of peaks and columns are provided along with recesses. The recesses of the surface are filled with plastic. Also, the cylinder sheath may include a layer of a porous ceramic material having a roughness.

BACKGROUND

Electrophotographic printing or copying devices are known for examplefrom U.S. Pat. No. 6,072,977 or DE 197 49 386 C2. They have a design asshown in FIG. 1. FIG. 1 shows a schematic arrangement of the componentsused for operation. An intermediate carrier 1 (in FIG. 1 this is aphotoconductor drum, but the intermediate carrier can also be aphotoconductor strip or band moves past components 2–7, 10–14 with aconstant speed. First, intermediate carrier 1 is charged by a chargecorotron 2. Using sharply bundled light, the image to be printed isproduced as a charge image on intermediate carrier 1 by a charactergenerator 3. Subsequently, the charge image is inked with toner in adeveloper station 4. Developer station 4 comprises at least one devicefor transporting the toner; this device transports developer 5, made upof toner and a carrier, to intermediate carrier 1. The toner therebymoves onto intermediate carrier 1 in the gap between developer station 4and intermediate carrier 1 in a manner corresponding to the chargeimages. Finally, the toner image is transferred onto a print medium 8,for example paper, in a transfer station 6, for example using a transfercorotron 7, and is then fixed in a fixing station 9 (not shown).Subsequently, intermediate carrier 1 is electrostatically neutralizedusing a corotron 10. The residual toner still adhering to intermediatecarrier 1 is removed for a new image cycle using a cleaning device 11,for example a cleaning brush 12 and suction unit 13. Finally, in orderto improve its long-term behavior, intermediate carrier 1 is exposedwith a discharge lamp 14. Intermediate carrier 1 is now ready for a newprint cycle.

FIG. 2 shows an example of a standard developer station 4 that containsa device 15 for transporting toner to an intermediate carrier 1. In FIG.2, the device for transporting the toner is realized as a magneticcylinder 16 having a rotating cylinder 17 that comprises an electricallyconducting sheath 22 to which developer 5 adheres, and having a magnetsystem 18 situated in its interior. Developer 5 is mixed in developerstation 4, and the toner is thereby triboelectrically charged byfriction. Corresponding to the magnetic field lines of magnet system 18,the developer then forms chains 19 that bridge developer gap 20 andcontact intermediate carrier 1. Due to the charge of intermediatecarrier 1 and the difference in potential between intermediate carrier 1and magnetic cylinder 16, the toner is detached from the carrier and istransferred onto intermediate carrier 1. The carrier then falls backinto developer station 4. Using a stripper 21, the thickness ofdeveloper 5 on cylinder sheath 22 is set.

A further developer station can be learned from U.S. Pat. No. 6,181,902B1. Here, a charged toner is moved past an intermediate carrier, via anapplicator cylinder that is adjacent to a pre-voltage, and charge imageson the intermediate carrier are thereby tinted.

In FIGS. 1 and 2, a magnetic cylinder is provided as an example of adevice for transporting toner to an intermediate carrier. However, thisdevice can also be an additional magnetic cylinder that conveysdeveloper to a magnetic cylinder or to an applicator cylinder,corresponding to U.S. Pat. No. 6,181,902 B1. Finally, the device canalso be used for cleaning an intermediate carrier, a cylinder thattransports toner, or an applicator cylinder. For this reason, in thefollowing reference will be made to a toner deposition unit, referringin combination to all cases of application of the device.

The devices used in electrophotographic printing devices fortransporting toner to or from a toner deposition unit thus comprise, asis shown in FIG. 2, at least one cylinder having a sheath (cylindersheath) to which the toner adheres. However, dependent on the electricalfield force on the correspondingly charged toner, the device is itselfsubject to an undesirable process of toner deposition on the cylindersheath. For example, there can be different potentials on theintermediate carrier (photoconductor drum, photoconductor strip)according to the discharge by the character generator or thenon-discharge, so that in discharged areas toner moves from the cylindersheath to the intermediate carrier, while in non-discharged areas toneris electrostatically deposited on the cylinder sheath due to theelectrical field distribution. Due to their electrically insulatingcharacteristic, these toner depositions result in a shielding againstelectrical charges, with the result that the transport of toner to theintermediate carrier is negatively influenced.

Systems are known that use a corresponding configuration of the magnetsof the magnetic cylinder and/or that use a blade in the vicinity of therotating cylinder sheath in order to bring about a constanttoner/carrier mixture relative to the rotating cylinder sheath (DE 10152 892.2). Due to the resulting mechanical friction between theferromagnetic carrier particles and the cylinder sheath, the tonerdeposited thereon is rubbed off, and is absorbed again by thetoner/carrier mixture.

However, dependent on the adhesive characteristics (materialcharacteristic and surface roughness) of the cylinder sheath, as well asthe physical properties of the toner and the carrier, the adhesiveforces between the toner and the sheath surface can increasesignificantly, making adequate cleaning more difficult. A significantamount of frictional or rubbing work is then required to remove thetoner from the cylinder sheath.

From the prior art, various constructions of the cylinder sheath areknown:

The subject matter of U.S. Pat. No. 5,851,719 A is a developer rollhaving a magnet in the interior and a sheath made of metal, providedexternally with a layer made of a resin, for example acrylic resin, thatis doped with electrically conductive particles. Using such a developerroll, ghost images and the arising of toner dust are supposed to beprevented during the developing of charge images on an intermediatecarrier. In addition, differences in charge in the toner particles,caused by the prehistory of the toner (fresh toner or residual toner)are supposed to be avoided. In addition, it is supposed to be achievedthat the charging of the toner is constant over the width of thedeveloper roll, independent of environmental conditions.

DE 41 28 942 A1 is based on the object of creating a developer devicewith which the image density is increased while the tonal values aremaintained, and in which line images are prevented from becoming denser.For this purpose, a specially constructed developer roll is providedwhose surface comprises electrically conductive first zones anddielectrically conductive second zones. The consequence is that thedifferent zones can be at different potentials, so that alternatingfields can be produced between the different zones, through which thetransfer of toner onto the intermediate carrier is controlled. In thisway, the advantages of a developer roll having a conductive surface incombination with those of a developer roll having a non-conductivesurface are achieved, or the disadvantages thereof are avoided. Adeveloper roll having a non-conducting surface accurately reproducesline fields in the desired shape and tones, while the image density isrelatively low; a developer roll having a conductive surface produces animage having a high image density distribution, but is worse withrespect to the line images. The developer roll is made of metal, forexample aluminum, whose surface is knurled in a meshed pattern. Theresulting recesses are filled with a dielectric epoxy resin, for exampletetrafluorethylene.

In EP 1 126 329 A1, a developer roll is described that is to have aparticularly smooth surface. For this purpose, the surface of thedeveloper roll comprises a layer made of ceramic material, namelyzirconium oxide or zirconium oxide with titanium.

The underlying problem of U.S. Pat. No. 6,026,265 A is to indicate adeveloper device in which, after developing, toner can be stripped fromthe developer roll without damaging or detaching the toner. For thispurpose, an application roll is provided that both supplies toner to thedeveloper cylinder before the developing and also strips off theremaining toner after the developing. The developer cylinder is made ofaluminum onto which there is applied a phenol resin containing carbon,in order to produce a surface having a particular degree of roughness.The application roll is made of a silicon foam or polyurethane foam,applied on a metal shaft. In addition, the surface of the applicationroll is provided with grooves in the longitudinal direction. In thisway, the supply of toner to the developer cylinder is improved, andafter developing the residual toner is securely stripped off of thedeveloper cylinder.

Finally, from U.S. 2002/028096 A1 there results a developer roll thatcomprises an electrically conductive shaft on which there is applied anelastic zone that is provided with a coating of resin. The elastic zonecan be made of rubber, and the coating can be made of a resin thatcontains carbon. With this realization of the developer roll, with theuse of single-component toner it is supposed to be achieved that given ahigh degree of electrical conductivity the roll can deform sufficiently,for example in contact with an intermediate carrier, and is elasticenough that it subsequently returns to the initial state.

In all these constructions of the cylinder sheath, the problem of thereduction of frictional work in the removal of toner from the cylindersheath is not addressed.

In PATENT ABSTRACTS OF JAPAN, vol. 2000, no. 20, 10 Jul. 2001(2001-07-10) & JP 2001 083795 A, a developer cylinder is described inwhich the surface is coated with Teflon or with a PTFE or PTFE derivate.Carbon is added to the layer in order to obtain conductivity.

PATENT ABSTRACTS OF JAPAN, vol. 010, no. 119 (P-453), 6 May 1986(1986-05-06) & JP 60 247669 describes a developer cylinder whose sheathis covered with a layer of PFA in which carbon powder is dispersed.

From PATENT ABSTRACTS OF JAPAN, vol. 017, no. 600 (P-1637), 4 Nov. 1993(1993-11-04) & JP 05 181366 A, there results a developer cylinder whosesheath comprises a metallic layer that contains PTFE.

PATENT ABSTRACTS OF JAPAN, vol. 007, no. 249 (P-234), 5 Nov. 1983(1983-11-05) & JP 58 132769 A discloses a method according to which alayer of PTFE is applied on the sheath of a developer cylinder.

PATENT ABSTRACTS OF JAPAN, vol. 1996, 29 Nov. 1996 (1996-11-29) & JP 08179616 A describes a sheath of a developer carrier that is covered witha resin layer containing conductive particles and particles having lowsurface energy.

From PATENT ABSTRACTS OF JAPAN, vol. 1997, no. 05, 30 May 1997(1997-05-30) & JP 09 026701 A there results a magnetic cylinder whosesheath is made of non-magnetic metallic material having electricalconductivity onto which a layer of non-rusting steel is thermallysprayed. The layer has a thickness of 10 to 100 μm, and has a roughnessof 30 to 100 μm. In this way, the adhesion of the carrier to themagnetic cylinder is to be reduced, and a long lifespan is to beachieved.

PATENT ABSTRACTS OF JAPAN, vol. 017, no. 529 (P-1618), 22 Sep. 1993(1993-09-22) & JP 05 142931 A describes a developer cylinder havingstrongly insulating properties. This is achieved in that an insulatinglayer made of αAl₂O₃ is applied, or a layer of aluminum oxide is sprayedon, in whose pores an insulating material is introduced.

From WO 03 036393 A, which does not enjoy prior publication, but has anolder priority date, there results a cleaning device for developercylinders. As a cleaning device a cylinder is used whose surface has alow mechanical energy. For this purpose, a Teflon layer can be appliedonto the cylinder, or an insulating material can be introduced intorecesses of a rough surface of the cylinder.

SUMMARY

It is an object to indicate a device, comprising a cylinder having asheath, for the transport of toner, constructed in such a way that asignificant reduction of frictional work is achieved in the removal ofthe toner from the cylinder sheath.

A device is provided for transporting toner in an electrophotographic orprinting or copying device comprising a rotatable cylinder having acylindrical sheath for the transport of the toner. The cylinder sheathcomprises a metallic layer having surface with a roughness such that atleast one of peaks and columns are provides along with recesses. Therecesses of the surface are filled with plastic.

A device is also provided for transporting toner in anelectrophotographic printing or copying device comprising a rotatablecylinder having a cylinder sheath of the transport of the toner andwherein the cylinder sheath comprises a layer of a porous ceramicmaterial.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an electrophotographic printing or copyingdevice;

FIG. 2 is a diagram of an example of a standard developer stationcontaining a device for transporting toner to an intermediate carrier;

FIG. 3 shows a first exemplary embodiment;

FIG. 4 shows a second exemplary embodiment;

FIG. 5 shows a third exemplary embodiment; and

FIG. 6 shows a developer station in which the device is used.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the preferred embodimentillustrated in the drawings and specific language will be used todescribe the same. It will nevertheless be understood that no limitationof the scope of the invention is thereby intended, such alterations andfurther modifications in the illustrated device, and/or method, and suchfurther applications of the principles of the invention as illustratedtherein being contemplated as would normally occur now or in the futureto one skilled in the art to which the invention relates.

The problem of very high adhesive forces between the toner and thesurface of the cylinder sheath, requiring a correspondingly high degreeof frictional work for an adequate cleaning, is avoided by the use of acylinder sheath having a particular design.

The properties of the surface of the cylinder sheath are set such thatthe adhesive forces to the toner are small. This can be achieved byselecting the surface energy of the sheath surface to be low. This alsoholds for metallic sheaths, made for example of high-grade steel oraluminum, which confer a very high degree of mechanical stability, butat the same time also have a high surface energy.

The cylinder sheath can advantageously be made of a metallic materialhaving a very rough surface. Due to the resulting peaks or columns, thesurface energy of the sheath surface is reduced, so that the developercan detach from the cylinder sheath through gravity alone. For furtherimprovement, the recesses in the surface of the cylinder sheath can befilled with a plastic that has anti-adhesive properties.

A further specific embodiment comprises the coating of cylinder sheathswith anti-adhesive materials in order to facilitate the removal oflayers of toner deposited thereon by mechanical friction, and in theparticular construction of the layer or of the layer deposition, inorder to ensure a flowing off of the electrical charge. Theanti-adhesive and electrically conductive properties are in additionmaintained over the entire life span of the device due to the speciallayer construction.

Coatings having low surface energy values can advantageously be achievedusing plastics, such as for example PTFE, PTFE derivates, or relatedmaterials, whereby closed PTFE coatings are to be avoided, because dueto their high electrical resistance they result in electricalinsulation, and thus to loss of the electrical charge transport from orto the metallic conductive cylinder sheath. It is therefore advantageousto construct the cylinder sheath from a coating having a low surfaceenergy, for example using PTFE or a PTFE derivate, which is then dopedwith an electrically conductive material, for example carbon.

In addition, it is advantageous to use PFA (polyfluoroalkoxy) as acoating.

Another advantageous realization of the cylinder sheath is one made ofporous ceramic material having a roughness of 2–80 μm. The pores can inaddition be filled for example with PFA, PTFE, or with a PTFEderivative.

FIG. 3 shows only a section through a cylinder 17, e.g. a magneticcylinder, of device 15 for transporting toner to a tenor depositionunit, and sheath 22 of said cylinder. The other components result forexample from FIG. 2. In addition, an enlarged segment A1 of a part ofcylinder sheath 22 is shown. Segment A1 shows a cylinder sheath 22having a metallic layer 24 and having a closed anti-adhesive layer 23that is electrically conductive.

Layer 23 is realized in such a way that an electrical charge transportcan be maintained. The layer can be made for example of PTFE doped withan electrically conductive material, e.g. carbon. Layer 23 can forexample also be realized with an electrically conductive PFA. The layerthickness can be up to several 100 μm. The specific volume resistancecan be in the range up to 10⁹ Ωcm. The layer can be deposited using aspray coating process in multiple layers of approximately 25 to 50 μm,and can be hardened in an oven.

FIG. 4 shows an additional specific embodiment of the present invention.Here, a cross-section of cylinder 17 with sheath 22 is again shown, witha detail shown in a larger scale as segment A2.

In this specific embodiment, the surface 26 of metallic cylinder sheath22 is realized in such a way that it has a very high degree ofroughness. A correspondingly rough surface, having peaks and columns 27,can be achieved either by partially wearing away the material (e.g. bysandblasting or etching) or by adding material (e.g. in a coating methodusing electrically conductive materials, e.g. CrNi plasma spraying,ceramic layer spraying). Such a construction of the surface of cylinder22 has the effect that the toner or the developer is detached from thecylinder sheath due to centrifugal forces and gravity. This effect ismade stronger if the recesses of the rough, electrically conductive,mechanically stable cylinder sheath are filled with a coating 25 made ofan insulating material or an electrically conductive material, e.g. PTFEor a PTFE derivate. The electrically conductive peaks or columns 27protruding through the coating thereby facilitate the electrical chargetransport, and the adjacent PTFE-filled regions 25 help fulfill theanti-adhesive requirements. The advantage of this layer constructionlies on the one hand in the increased mechanical stability of thesurface (stabilization by wear-resistant columns or peaks) and on theother hand in the ensuring of a charge transport via the electricallyconductive columns or peaks 27, which at least in part protrude pastcoating 25. Electrically insulating PTFE materials can hereby also beused for the filling.

The coating of cylinder sheath 22 in order to achieve a high degree ofroughness can take place for example through the application of athermally sprayed CrNi layer. Following this, the filling of therecesses of rough surface 26 can for example take place with aconductive PFA. The layer thickness can be up to several 100 μm. Thespecific volume resistance is in the range up to 10⁹ Ωcm. The layer canbe applied using a special spray coating process in multiple layers ofapproximately 25 to 50 μm, and can be hardened in an oven.

FIG. 5 shows a third specific embodiment. Cylinder sheath 22 is againshown in cross-section, and a segment A3 thereof is shown in an enlargedscale. The combination of anti-adhesive properties, electricalconductivity, and mechanical stability is achieved through the use ofcomposite materials 28. Composite materials can for example beconstructed from porous thermal ceramic sprayed layers, whose specificvolume resistance (electrical conductivity) is set by the mixing ratioof various oxide ceramics. The pores 29 of the spongy, mechanically verystable ceramic structure are filled with a material having low surfaceenergy. The advantage of this layer construction lies in the very highmechanical stability due to the spongy ceramic structure and thepossibility of setting the electrical conductivity within wide limits.The required anti-adhesive property is maintained by the regions filledwith materials having low surface energy. Because the spongy, filledstructure is present throughout the entire layer volume, theanti-adhesive and electrically conductive requirements on the surface ofcylinder sheath 22 are maintained even when there is wear.

The coating of cylinder sheath 22 with a porous ceramic sprayed layertakes place for example with a mixture of aluminum oxide and titaniumoxide, but can also take place with other ceramic materials havingsimilar physical properties, such as for example chromium oxide. Thespecific volume resistance of the layer material can hereby be set viathe mixing ratio of the initial materials. The porosity that can beachieved in the manufacturing process is in the range of approximately20%, whereby the average pore diameter is from 20 to 100 μm. After thethermal spraying, the pores are infiltrated with a thin flowing polymerlacquer, for example PFA, or other polymers having anti-adhesiveproperties (PTFE), under normal air pressure conditions or in a vacuumchamber. The polymer material thereby penetrates into the porousthermally sprayed spongy carrier material, down to the base of thecoating. The anti-adhesive material can hereby be realized so as to beinsulating or electrically conductive, because the electrical chargetransport takes place via the ceramic framework, which is porous and canbe electrically adjusted.

In the exemplary embodiments, the cylinder sheath can also comprise afirst layer made of an electrically non-conductive material, for examplea plastic, onto which the electrically conductive anti-adhesive layer isthen applied.

From FIG. 6, there results a developer station corresponding to U.S.Pat. No. 6, 181,902 B1, and DE 101 52 892.2. Depicted is an example of adeveloper station 30 that is used for a strip-shaped intermediatecarrier (not shown). In the following, only those components ofdeveloper station 30 are explained that are required for thespecification.

Developer station 30 comprises a developer chamber in which thedeveloper, made up for example of toner and carrier, is contained, andin which the components used for the developing are situated. In theexample of FIG. 6, these components are:

-   -   an applicator cylinder 31 that is situated adjacent to the        intermediate carrier and that transports toner for developing        the charge images through the tinting gap formed between        applicator cylinder 31 and the intermediate carrier;    -   a transfer cylinder 32 that is made up of a movable sheath and a        magnet situated in the interior and that transports developer        from the developer reservoir into the vicinity of applicator        cylinder 31 and that is adjacent to a voltage that differs from        that of the applicator cylinder, in such a way that the toner        moves from the transfer cylinder to the applicator cylinder;    -   a cleaning cylinder 34 that cleans off the toner remaining on        applicator cylinder 31 after the developing.    -   a blade cylinder 33 is also provided.

The developer, made up of carrier and toner, is transported by transfercylinder 32 from the developer reservoir into the vicinity ofapplication cylinder 31. Due to the voltage present between applicatorcylinder 31 and transfer cylinder 32, the toner is taken over fromapplicator cylinder 31 and is moved past the intermediate carrier, sothat toner moves onto the intermediate carrier in a manner correspondingto the charge images thereon. After the tinting of the charge images,toner that still adheres to applicator cylinder 31 is cleaned bycleaning cylinder 34.

Cleaning cylinder 34 is in particular realized corresponding to FIGS.3–5. It is particularly advantageous if the cylinder sheath of thecleaning cylinder is realized in a manner corresponding to FIG. 4,whereby it is especially economical if the rough surface of the cylindersheath is not filled with an anti- adhesive plastic. The precisefunction of such a cleaning cylinder can be learned from DE 101 52892.2.

While a preferred embodiment has been illustrated and described indetail in the drawings and foregoing description, the same is to beconsidered as illustrative and not restrictive in character, it beingunderstood that only the preferred embodiment has been shown anddescribed and that all changes and modifications that come within thespirit of the invention both now or in the future are desired to beprotected.

1. A device for transporting toner in an electrophotographic printing orcopying device, comprising: a rotatable cylinder having a cylindersheath for the transport of the toner; the cylinder sheath comprising ametallic layer having a surface with a roughness such that at least oneof peaks and columns are provided along with recesses; the recesses ofthe surface are filled with a plastic; and the cylinder comprising acleaning cylinder for a toner deposition unit.
 2. A developer station inan electrophotographic printing or copying device, comprising: atransfer cylinder that transports a developer comprising toner andcarrier to an applicator cylinder; the applicator cylinder takes overthe toner from the developer and transports it past an intermediatecarrier; adjacent to the applicator cylinder a cleaning cylinder devicethat cleans residual toner and developer from the applicator cylinder;and the cleaning cylinder device comprising a rotatable cylinder havinga cylinder sheath, the cylinder sheath comprising a metallic layer witha surface having a roughness such that at least one of peaks and columnsare provided along with recesses; and the recesses of the surface arefilled with a plastic.
 3. A device for transporting toner in anelectrophotographic printing or copying device, comprising: a rotatablecylinder having a cylinder sheath for the transport of the toner; andthe cylinder sheath comprising a layer of a porous ceramic materialhaving a roughness of approximately 20–80 μm.
 4. A device of claim 3 inwhich the pores are filled at least partly with plastic.
 5. A device ofclaim 3 in which the pores have a diameter of approximately 20–100 μm.6. A device of claim 3 in which the plastic comprises PFA.
 7. A deviceof claim 3 in which the plastic comprises at least one of PTFE and aPTFE derivate.
 8. A device of claim 3 in which the layer comprises avolume resistance in the range up to 10⁹ Ωcm.
 9. A device of claim 3wherein the cylinder comprises a magnetic cylinder for transportingdeveloper to a toner deposition unit in a developer station of theelectrophotographic printing or copying device.
 10. A device of claim 3wherein the cylinder comprises a cleaning cylinder for a tonerdeposition unit.
 11. A developer station in an electrophotographicprinting or copying device, comprising: a transfer cylinder thattransports a developer comprising toner and carrier to an applicatorcylinder; the applicator cylinder takes over the toner from thedeveloper and transports it past an intermediate carrier; adjacent tothe applicator cylinder a cleaning cylinder device that cleans residualtoner and developer from the applicator cylinder; and the cleaningcylinder device comprising a rotatable cylinder having a cylindersheath, the cylinder sheath comprising a layer made of a porous ceramicmaterial having a roughness of approximately 20–80 μm.
 12. A device fortransporting toner in an electrophotographic printing or copying device,comprising: a rotatable cylinder having a cylinder sheath for thetransport of the toner; and the cylinder sheath comprising a layer madeof a porous, thermal, electrically conductive ceramic sprayed layer. 13.A device of claim 12 in which the pores are filled at least partly withplastic.
 14. A device of claim 12 in which the pores have a diameter ofapproximately 20–100 μm.
 15. A device of claim 12 in which the plasticcomprises PFA.
 16. A device of claim 12 in which the plastic comprisesat least one of PTFE and a PTFE derivate.
 17. A device of claim 12 inwhich the layer comprises a volume resistance in a range up to 10⁹ Ωcm.18. A device of claim 12 wherein the cylinder comprises for transportingdeveloper to a toner deposition unit a developer station of theelectrophotographic printing or copying device.
 19. A device of claim 12wherein the cylinder comprises a toner deposition unit.
 20. A developerstation in an electrophotographic printing or copying device,comprising: a transfer cylinder that transports a developer comprisingtoner and carrier to an applicator cylinder; the applicator cylindertakes over the toner from the developer and transports it past anintermediate carrier; adjacent to the applicator cylinder a cleaningcylinder device that cleans residual toner and developer from theapplicator cylinder; and the cleaning cylinder device comprising arotatable cylinder having a cylinder sheath, and the cylinder sheathcomprising a layer made of a porous, thermal, electrically conductiveceramic sprayed layer.